Guess you are looing forward to import the expenses in Accounts Payables Module of GP.
If your using eConnect or intergration manager
For header refer to this.
msdn.microsoft.com/.../jj193390.aspx
For distribution refer to this.
msdn.microsoft.com/.../jj193388.aspx
If your are using concur integrator refer to this:
https://community.dynamics.com/gp/f/32/t/61237.aspx#.UjQI3TDnbKI
Sanjay