@Jagjit Singh Welcome to BP
First you might mention what size multi family you are talking about. The process to buy a 100 unit building is very diferent than say a 3 unit building. Esentially a small mutil family is not much different that buying a single family.
If you are stugling at that level my advice is go out and leran the market. It is great to know the strategies and the ways to evaluate a deal but if you do not Know the Market fully and deeply you don't know what numbers to plug in the formulas to evaluate a deal. You don't really know what a good deal looks like (or bad deal)
If you are buying large multi family prperties we have a multi family forum here you can check out. However if you are buing 1-4 unit buildings go out and look at lots of deals. What kind? Look at Listed properties, open houses, for sale by owner (FSBO), wholesalers deals, any on site auctions you can find, and look at as many deals other investors own that they are willing to show you.
Ask the investor what are his numbers, what does he intend to do with the property, how much is it worth when done, how much does it need in repairs and what repairs will he or she be doing.
When you know your market inside out you will feel more confident on moving forward. You won't learn this sitting behind a computer screen. You leran it by going out and looking at real properties. Good Luck