is task based testing a good way to gather user's opinions and research UX and usability of app? By task based testing I mean we have app for certain type of users, so we gather few people that fit in this target group and we give them set of tasks to complete inside the app - without explaining them this app, just like normal user would use it. Tasks are created based on how user would use this app. So e.g. if it's shopping app then one of the tasks would be to find product X, Y and Z from different categories, add them to cart, select delivery address and complete purchase with specified payment method. Then I would check if they were able to complete these tasks (maybe they couldn't find a product) and ask for their opinion on each step of the flow. Was it easy to find product X? Did you see there's search and you can search in specified categories? Or stuff like that.
Is that a good way to do it? Are there better ways to do it? Are there any specific things I should pay attention to? Should I also record screen to get full insight of what they did or that won't give me more info than what I already can gather by asking questions?
Sorry for noobish questions, but I'm not an UX specialist. I never did such research. I tried to google it, but mainly found surveys and interviews as a way to gather user feedbacks.