Hey All, i've largely done only cardio training in the past, i'm going to start resistance training now. my questions are

1.) how soon will i start to see weight gain from resistance training? i've been told i wouldnt see anything till 8 weeks or so.

2.) if i do not want to gain any more weight (muscle wise) should i just be doing low weights and high reps? Should my low weights still be challenging or should i be able to do 12 - 15 reps comfortably, and not struggle towards the end.

What are your goals? Gaining lean mass is hard as hell and anyone who tells you different is lying or ignorant. Just lifting weights does not = muscle gain. If you lift weights while in a caloric deficit you may see some initial gains because you are a newb but nothing drastic or sustainable.

To gain lean mass you have to

Eat big
Eat clean
Lift heavy

I can't really get what your goal is. If you will clarify with some stats and goals I, or someone else may be able to help a little more.

I just want to tone up, i dont want to bulk up at all. if anything, i'd like to lose about 10 pounds.

Male or female?

If you're dieting, what makes you think you're going to get bulky?

Then I assume you will be in a caloric deficit so its pretty much a non-issue. What is an issue is muscle retention. As you get closer to goal i.e.10 lbs like you are, your body is really going to want to hold onto the reserves(fat) and will be willing to sacrifice a little muscle. You can counter act this by lifting heavy and getting plenty of protein (aim for 1g per lb of body weight). Don't worry about bulking up, trust me its hard enough when trying, you aing gonna do it by accident.

I'm a male, 29 years old.

Nothing is really making me think i'm going to get bulky.. i just want to tone up. i dont know a lot about it is all, since i've done cardio so long.

Sounds good, today was actually my first day lifting weights. arms feel like jello