While I do highly recommend you get coaching for this (your question is essentially asking "How do I solve a case well"), I can provide some initial guidance here.
Hypothesis-driven - We are no longer singular hypothesis-driven, stating this boldly at the beginning of the case. Rather, we are hypotheses-driven or objective-driven. This is very different.
Your entire framework is a set of hypotheses and views as to how to solve a problem.
You don't need to state it explicitly, but remember that 1) You need to always be thinking about one and 2) You need to be demonstrating your drive towards one.
Also, remember that a hypothesis isn't necessarily "I believe x is the cause". Be better hypothesis is "If we can see what's happening with A, and A is going up, and then we look into B and B is big, then x is likely the case".
A hypothesis is much more about what questions do I need to ask/answer and how, in order to see what's happening.
Another way of viewing it:
Your framework is your structure for approaching the problem. It consits of a few main areas you'd like to look at. Inherent in your framework is a view that "If I answer A, B, and C, then we have an answer"
So, for market entry:
1) If the market is big, and it's growing, then we still want to considering entering
2) If #1 = yes, then let's see if it's attractive...can we win there? Is our product good/better than our competition's? Etc. If yes, let's definitely consider entering.
3) If #1 and #2 = yes, then, when we do enter, are we sure we can win? I.e. do we have the right plans. Will implementation actually pan out? Do we have the expertise, capital, etc.? In other words, if #2 is the thearectical, #3 is the reality.
Then, your summary becomes "I believe we should enter the market, if we can prove it's a good market, the it's attractive to us specifically, and that we will win it".
^Now this is a hypothesis :)
Read these 4 Q&As for some great context + discussion:
Hope this helps! This is a tricky topic that's difficult to properly answer in writting...if you want a more thorough explanation, and training in the mindset shift required here, don't hesitate to reach out!