you can concentrate to make a set of portals wherever you want as long as you concentrate long enough(can be as big or small as you want, bigger it is requires more concentration) small: instant  medium: 1 minute large: 30 minutes huge: 1 hour giant: 5 hours. one portal always opens 3 feet in front of you while the other opens where you think of while concentrating. can only be used 1 time every 2 days, if used more than 1 you get a level of exhaustion and lose an action on your next turn 

Notes: Bonus: Intelligence Ability Checks, portals can only be used by dragonborn otherwise its a normal basic wand