Wood design strengths can come from the southern forest production association which has their strength spec books published on their website. There is a ton of service factors that can be applied to the wood but since you are indoors you can Add a bit more to the design strength they provide. Bad news is wood from home depot should be considered a #3 or #2 at best so the allowable stresses are even more trash. If its permanent you cant take the additional 33 percent overstress factor either.
As Fred said above deflection criteria of L/720 would be pretty conservative because it just doubles the standard ASD and lrfd live load deflection limits.
Not sure if mechies get into these kind of deflection criteria but essentially it is as simple as it looks take your span length in inches and divide by 360 for live loads and 240 for dead loads or double up the 360 for 720 to have a stiffer floor span which is nice to do.
Floor loads for a residential application is something i wouldnt know but im sure it wouldnt be too hard to find or Fred might have them off hand. Snow load might be pretty heavy where you are and you have to determine if any walls are going to put big point loads on the beams because of it as well.
Simple bending calcs using a simply supported beam would work with double integration deflection method if you have an odd loading setup, or some software if you dont want to do all that work, skyciv isnt bad but the freebee is limited on what you can add into your loading, or Risa 2d educational is floating around but Risa always pissed me off.
Bending stress =m/s is effective for the stress calc, which can dictate with wood when it is uncommon with other materials.
If you wanted to get crafty you could count the decking into your calcs and run a quick one for the shear flow through the nails which would juice up your I a bit which is fair for real world applications but i typically havent seen it done, though i normally design support of excavation kind of shit when using wood not residential work.
You can back calc in assuming a 2x10 is sufficient for the span if its already in place as such, which will help give you some bearing as to where your numbers should be around. Or if its something like tji floor joists they have a whole heap of info on their site, they are the wooden i beams, they are easy to identify if you have them.
If you are doing a small area hand pick your floor joists and always grab the heaviest ones as long as they are not full of water. And remember the grading for wood is a visual process so if you pick some nice looking heavy boards you can rest easy knowing that you exceeded your design. Pretty obviously dont grab wood with knots and problems on the outer edge for I and for the love of God make sure you or your electricians and plumbers drill through the middle the joists and not at the bottom like they always try to do when they are rushing.