Im new to the armored core sieres i only got the acfa about a week ago its an awsome game but i dont really understand the Stabilizers and the tuning can anyone help me please?

I don't understand about the stabilizers either, but I know a little bit about tunning. Tunning only available for you to change after completing a certain or specific missions.

Stabilizers affect the lean of your Next. It is essentially how much your mech leans in one particular direction. If you Balance all sides to say 200 then your mech is perfectly centered and will not be slowed down while attempting to boost in Either direction. Where as if you were to say have 250 forward lean and 150 Back lean you would go forward faster. Or at least that what the game has lead me to believe, and I can see no other conceivable way to label the stabilizer system. The Tuning just increases the effectiveness of your AC's parts. KP output Increases the Speed at which your AC regains Primal Armor, and things like Load increase the Load Tolerance of your Next's Legs allowing them to carry more.

I personally let the auto-tuner do the tuning and use the stabilizers as coolness-enhancers.
I usually only use a NEXT that uses dual blades and either dual Gatling Guns (GA) or Dual "Heavy" Grenade Cannons (Arisawa Heavy Ind.)
Btw... I started off with Interior and beat the White Glint levels with luck. I can't beat them again to save my life.

Yes, stabalizers balance out the load and make it more balanced, as explained. Tuning specializes your AC. You can tune PA to max to make the Primal Armour stonger, etc. based on your fighting style.