Hi!, well , im kinda noob, but ive been playing with ardour to set up my recording enviroment , in ubuntustudio , i have an echo 12 card which has 12 analog ins and 12 analog outs, ive set up my jack conections , and i can record and listen later what ive recorded and all very well. The thing is that i record something , and then i wanna record something on top (to, let’s say, correct a guitar solo, or add a hit on a drum over an existing drum rithm), when i arm the ardour to record, everything that is below stops sounding and then i can only hear what is on top ( the latest region), i howld like to know how to record something on top of something else in the same track and still be able to hear both recordings on the same time while i record and after, i read that it might be a problem with monitoring so i made " ardour does monitoring" but there was no change.
Appritiate any halp , Thanks a lot!! 
Ardour is a “multitrack” DAW (which I think all DAWs are), multitrack means that everything you record has to go onto its own track. Go to session and click Add track for every instrument you want to record and do record each instrument into a different track, then you should get better results.
Did I hit the nail?
Don’t confuse regions with tracks.
Please read manual.
What your asking for could be answered in a couple of ways. There is a way to switch regions so that when one is over the top of another you still hear them both. To do this, right click on a region and from its context menu select ‘transparent’. However I think you are asking something more complicated. When a track is in record you will always hear the audio from the tracks input, your guitar or drum for example. When a track is not in record you will hear the playback of the track itself. This is pretty standard. It could be possible, and this has been discussed but not implemented, to have a function that allows you to hear the input and the playback at the same time. This can be a very useful feature for doing punch ins and overdubs. But, the question still remains, should you really hear something other than the thing you are recording when you actually start recording ? As @joegiampaoli said though, you have multiple tracks available to you, create a new one for a new recording. You can then hear both things, and possibly move the region onto the track you need it to be on, after you have recorded.
Also investigate punching in and out in the manual that was linked in the previous answer.
Thanks , i used the transparency thing and worked fine in the playback , and olso ( finally) found the adour mechanics for Punching, but i would really want to be able to hear my input and playback at the same time, just beacuse i moved to ardour from sonar when i moved to ubuntu from windows ( yay!) and i am used to work this way, im posting a new thread on this topic, but thanks anyway crhis , you were very helpfull :).