Amb musics and Modeling?

[Slanderous]

You can use sounds tool in level editor to add various ambience sounds around your map.
To place a sound, click on the speaker icon located on the toolbar. Put one anywhere you like, click on it, choose a sound that you want it to play, change the min and max distance (the distance where the sound can be heard), tweak the volume, etc.

To simulate a sun effect, place a bilboard above your map, as the bilboard material select "bb_white_halo.mat". Set it wherever you want, change the color to one that you want, resize it so it actually looks like a sun. Then, place a spotlight next to your sun, change the radius to a value that covers up most of your maps, change the colour so it looks like your bilboard sun, and tick "cast shadows" if you want, so it casts some jolly shadows obviously.

Here's a very quick (and shitty) example on how the sun thing looks like if you spend at least 5 minutes on it. Behind the spotlight is hidden a bilboard if you can't notice.

Spoiler below!

About your texturing question, Jesus man, you have the whole internet in front of you. All you need is google "how to make textures for models in maya". Most of people that are pro at modelling spent hours of hard work to study how to do stuff, and they didn't beg someone for help. The more you work on things, the better things you get.