external preamp with the xr18 questions plz help me

uHi im elie im a young engineer and im trying to figure certains things out. im looking to buy a midas verona and use it as external preamps and eq's for my behringer xr18 (recording purpose). Do I need to hook up the xr18 in the combo jack using trs jacks or i need to use male xrl's to have acces to the line input. there is no internal switch between mic and line and i want the least colored sound possible by the xr18. I did a little research but there is no exemple with the xr air so i dont even know if there are to circuit, one for line and one for mic or you just put down the gain on the mic pre. In that case do you think it will color the sound badly and ruin my external preamp effort. thanks for the repons and sorry for my bad english lol.