Log in all your alts on desktop, then log in one character on phone or tablet. All of your linked alts will be pulled into that device too.
When you open the web site in Safari on iPhone or iPad, you will get a notice at the top instructing you how to install it on your Home screen. Notifications will not operate on iOS until you do that, so I recommend you do it immediately and continue setup from there.
Similar to my Wayfinder, this is another multi-server setup but not as many.
Web handles all communication with the user and with ESI.
Cache is where mail headers rest after a pull so all your clients can be notified. Other mail data can land here briefly based on user actions. No mail data obtained from ESI lives here longer than five minutes.
Database is where your login tokens, alt linking, and session tokens are stored so Web and Cache can keep your mail and your notifications straight. Your mail, headers or otherwise, never touch the database.
Remember to check this out. Not only is it one of the few options for push while apps are closed, but it also doesn’t require you to repeat your SSO login on a regular basis.