I know you said you are new to Warhammer and you want to avoid magic. What the other posters have indirectly provided is a huge aspect of Warhammer Fantasy - magic defense. Even if you arent going to have a magic focus for your army, you need to be able to counter enemy magic. Spells can be just too good to sit back and idly let your opponent toy with you.
So, without making your army focus magic (and you dont even really need to cast a spell if you technically dont want to), you need to have what is commonly known as a Scroll Caddy. This is a Wizard with some Dispel scrolls.
I dont know if you are familiar with the magic phase, but you will get 2 dispel dice automatically and +1 per every Level 1-2 Wizard, +2 for every Level 3-4 Wizard, and then extra dispel dice from items.
During your opponent's magic phase, whenever they cast a spell you can try to dispel it by rolling your dispel dice and trying to roll higher than their roll to cast. It *definitely* behooves you to be able to dispel magic. This can be a very big part of the game.
So, the answer? Take at least 1 Wizard and load him up to counter magic. That way you have a strong anti-magic presence without having to dabble in magic yourself, if you dont feel comfortable with it.
What others have recommended is to turn that Ancient Stegadon into an Engine of the Gods. This means taking a Skink Priest and mounting it on an Engine of the Gods (an Ancient Stegadon with pluses). You'll see the information about the Engine of the Gods on page 55 of your Lizardmen Army book. Take note of the special powers it has, as well as adding to your dispel dice.
Now, if you turn to page 93 of your Lizardmen Army book and find the Skink Priest entry, you'll see he can take "Ancient Stegadon with Engine of the Gods" as a mount.
So there are some of the basics. If you are staying away from being pro-active with your magic, and instead intending to play a pure combat game, I'd make the following suggestion:
That Skink Priest on your Engine of the Gods can carry magic items. Give him a Diadem of Power (page 102 Lizardmen Army book) and a Dispel Scroll. Each item costs 25 pts. The Diadem of Power lets you take up to 2 of your Power Dice (generated during YOUR magic phase) and save them to use as dispel dice during your opponent's magic phase. Since you dont want to get involved in magic, this gives you the ability to counter a *ton* of magic. And just in case, you have a dispel scroll. This is a one use only item, but as soon as you use it, the spell that your opponent was trying to cast gets immediately dispelled. While there are exceptions to every rule in this game, the Dispel Scroll will let you counter something particularly nasty if you dont want to risk rolling dispel dice and maybe not countering it.
Summary:
Skink Priest at Level 1 - 65 pts
Engine of the Gods mount - 290 pts
Diadem of Power - 25 pts
Dispel Scroll - 25 pts
Total - 405 pts
4 Power Dice
4 Dispel Dice +2 if you use Diadem of Power
1 Dispel Scroll
While this is in no way a magic heavy army, it will let you counter the nastiness which is enemy magic and still be able to cast a couple little spells to get the feel of the magic system.
If you wanted to explore the magic system a bit more, you could bump your Skink Priest to a Level 2 Wizard. This only costs 35 pts and gives him +1 Power dice and an extra spell.
