In the main header navigation on the web, click on the settings (gear) icon, then integrations. Sign in with your Esri username and password under your Edge user account. Once signed in, your mobile client will have access to your basemaps. Just go to map view, then tap the select map button at the top left, and you should see them in your list. You must be signed in with the same user account on your mobile that you connected through the Edge Server integrations page.