At first launch aceminer autodetects GPU settings and prompts for pool account settings.
These settings are in config.xml in the aceminer folder.
Edit config.xml in notepad:

Pool settings is in <PrimaryConnection> group:
<ConnectionAddress> pool address
<ConnectionPort> stratum port
<Ssl> (true or false) – enable or disable encrypted pool connection (must be supported by pool)
<Login> your pool login
<Password> pool password. Note for f2pool cannot be blank
<SecondaryConnection> is a failover pool details group which is unfilled
Fill your secondary pool details manually to enable failover pool.

Save changes and close notepad.
Run start.bat to continue mining.
Tested configurations for f2pool and sparkpool:
<PrimaryConnection> <ConnectionAddress>grin29.f2pool.com</ConnectionAddress> <ConnectionPort>13654</ConnectionPort>
<Ssl>false</Ssl>
<Login>aceminer.1080TI</Login>
<Password>x</Password> </PrimaryConnection>
<PrimaryConnection>
<ConnectionAddress>grin-eu.sparkpool.com</ConnectionAddress> <ConnectionPort>6666</ConnectionPort>
<Ssl>false</Ssl>
<Login>aceminer@email.com/1080TI</Login> <Password>111</Password>
</PrimaryConnection>