Hi Kitz. Don't worry about the questions being basic, it's good to cover everything. Lots more people will be wondering and not asking, trust me!

In early pregnancy you just need to limber up more - your joints get more flexible and if you don't warm up properly then they end up hurting! You can still do exercise, but you'll find yourself running out of breath earlier. You should cut back on contact sports, dropping them entirely after the 1st trimester, but otherwise it's up to you how comfortable you are. I was doing yoga and bellydancing right up to 9 months and running at 8.

Diet... you need to avoid raw eggs, unpasturised cheese and shellfish - on the main articles on this site there's a big list. Just be sensible and it will all be OK!