Okie so it means this, here is the diagram first
1. C is between A, B and AC:CB = m:n
so from this we can conclude
so cross multiply yields nAC = mCB
therefore
2. D is not between A,B and AD:DB = m:n.
doing the same as part 1. yields
But we know m > n > 0 so for example to get an idea of the diagram let m = 4 and n = 2
this means
which is same as saying AC = 2CB, so this means AC is TWICE the length of CB, and in the diagram you can see this
the same goes for AD, so
, so this means AD is TWICE the length of DB, again in the diagram you can see this.
Now that just gives an idea of the diagram, obviously we don't know the values of m and n, but at least now you can have a good idea of the diagram to do the question.