hello
i need to know how much current can draw a track with width 1mm
also i need to know how much current a vias can draw ( so with more vias i obtain the current i need)
is it possible put more vias between a tgrck on bottom and on top to draw thw current i need ?
if i have a big surface pin for a connector smd i can put on it some vias to go on a trck on bottom layer ? i have drc error but i think is possible ignore it.
- i do not know how i can place component on bottom layer
thank you
Brand new interactions and interfaces. 
Easy to use and quick to get started. 
Depends on the voltage. Start with https://www.allaboutcircuits.com/tools/trace-resistance-calculator/ to calculate the resistance of the tracks.
If you are talking 100mA or more, always use multiple vias. If in the Amps then make the vias much larger diameter than the default, or preferably put a component leg through the hole(s) so it is soldered solid.
Never put vias under the actual SMT pins apart from large surfaces where they are designed to do this - for example SMT power transistors. Instead make the pad larger and surround it with vias to transfer current and heat away.
Select the component to go on the bottom layer and change the Layer menu item in top right corner to BottomLayer
And never ignore DRCs. It's a bad habit that will bite you at some time in the future. Fix the problem even if it means changing the design a little. A classic is the use of a 0 Ohm resistor so that two ground nets are separated.