The "For Dummies" series of books has a "Buying and Selling a Home For Dummies" book which I found useful a million years ago when I bought my first house. I assume it has been updated since then :-) Make sure you buy the UK edition as real estate systems vary widely around the world, indeed the systems are even completely different between England&Wales vs Scotland within the UK. They also have online "cheat sheets" to supplement the books: https://www.dummies.com/personal-finance/real-estate/buying-and-selling-a-home-for-dummies-cheat-sheet-uk-edition/
However, what no book or website can tell you is whether it is better for you to buy a house vs rent a house, as this will depend far too much on the details of your specific personal and financial circumstances. One thing I would say though, is don't think of it as "which is more profitable" (as in your question) - renting vs buying a home to live in is not about profit, it is about finding somewhere that is comfortable and suitable for you to live in and making sure that you are not spending more than you can afford in order to do so. Yes, if you own the house it might appreciate in value over time, but a) real estate crashes happen so you can't assume it will always get more valuable and b) even if it house prices continue to rise and your house becomes "worth more money", you can't easily liquidate that money because you still need somewhere to live - and if house prices have risen in general then anywhere else you might move to has also gone up in price at the same time.
Also the renting-vs-buying calculation is about a lot more than just the rent vs mortgage cost. When you own a home you also need to factor in the costs of building insurance, maintenance and repairs. There are also costs associated with buying and selling (surveys, conveyancing, local authority search fees, stamp duty...) that you should be aware of.
On question 3, and specifically for England&Wales, you can do two things in parallel: start looking at Rightmove and/or signing up on estate agents' mailing lists to be notified of properties that fit the kind of thing you are looking for, and talk to your bank about the amount of mortgage you would qualify for. They will undertake a detailed audit with you of your incomings and outgoings and tell you how much they are in principle prepared to lend you, which alongside the amount of savings you have to cover a deposit will tell you the budget range you should be looking in. You should also do your own budget analysis to figure out what you think you can afford rather than blindly assuming that if the bank will lend it to you then it must be OK. Remember to think about what happens if mortgage rates go up, as they can only do from where they are at the moment.