How to test a system alone with very little experience?
I have little experience with testing and I'm being hired to work on a team where I am the only tester. I'm struggling to find the best approach for the process. Being alone should I write down a test script or not? Wouldn't it take too much time?
I have no experience in writing test scripts, could anyone help with a good reference (book, video or whatever), please?
Welcome to the site!
Your situation might be a difficult one for a couple of reasons:
you're new to the testing and you don't know much about the process, about the technical stuff, and about yourself in such a situation
you're the only one on the team who is supposed to test; I find this the biggest obstacle because you basically have nobody to ask for advice in testing; don't expect developers to contribute much in this area
other things just might make it worse: it's also a new company for you, new people, new product, new industry, there's no good project management, people are overworked, the project is seriously behind a schedule, the project is understaffed, etc. etc.
However, you need to start somewhere and there's no going back, so start thinking about what you can do:
start with your attitude - I've never been looked down upon even when I messed up when I also showed I cared about the result and about me learning whatever I messed up; if you show you're willing to work on yourself, people will give you time and space to do so; don't be an enemy with the developers, start working on the product with them, then they will help you out, give you enough information about new features, etc.
you can learn the product first - use the product as the user you make this product for; at the end of a day, you're testing for such people (I assume here the product is meant to be used by somebody and it's not some API or sth.)
learn the big picture first and details later when you already have the framework in place
improve your technical skills - data formats, tools, APIs, scripting/programming languages; better start slowly here, start with what you really need on your project, there'll be time to learn what you're interested in and what's not needed on the project later
ask questions - even if you are the only Tester there, there might be a project manager who might know the product very well, ask them questions, ask other people who know the project; however, be aware that developers might not know much about what's beyond the code; so better ask them only specific questions about some parts, that's where they can give you really good answers
improve your test cases - I think it's always a good idea to write at least some of them down, it makes you think about the system a bit more, it makes you focus at the task and you might come up with more good test cases; writing test cases down shouldn't take you much time away from testing, but I suppose you can find at least some time to do this; consider positive and negative test cases, pay attention to empty/null values/field, think about different combinations and states
read about the product if there's something to read - there might be some documentation, test cases, use cases, former bugs, etc., find some time to read some of these, it helps you learn the product and e.g. common bugs and/or areas where you can expect more problems in the future
don't be afraid to say what you need to do better testing - maybe you need just a little bit more time to perform some testing before the next release, try to negotiate what you need in such situations, but don't be angry if you're not given it, simply work with what you have
and honestly, and I hope it won't go this far, set some limits to what you're willing to do and if the project goes beyond these limits, be willing to walk away; don't share this with other people in the company, but you need to be able to say no if there's something seriously wrong with the project/company, etc.; this should be the last course of action, but you need to be prepared even for this scenario
if you want to read something on the Internet about testing, I recommend more concrete advice now and you can go into more philosophical topics later; so e.g. if you're testing something in e-commerce, you might find some concrete articles like 8 Important Segments Of Testing eCommerce Websites; be aware that nothing will be complete, you need to slowly piece it together from different sources
I hope I've helped a bit here. It's not as cut and dried as I might've made it look like here, you always need to consider your context and your situation.