first time going to a Texans game.. advice?

Me and my girlfriend are going to our first Texans game this Sunday. We have all day Saturday in Houston, what are some things we should do? Activities, restaurants, etc? Figured recs from Houstonians would be better than a google search.

Also, we want to tailgate for the game but we won’t have our own vehicle since we are flying. Can we just hang out with everyone who is tailgating? Do we have to pay to get in? Also best lot/lots for tailgating? Appreciate any advice in advance, Go Texans!