To earn Gridcoin in solo staking mode you need to run the Gridcoin client and continuously stake.
If you have not yet installed the BOINC client, you should read the BOINC installation guide to setup BOINC. The BOINC client has to be installed alongside the Gridcoin client in order to verify BOINC account ownership and to access local BOINC statistics.
Once the client launches, enter your email address when prompted to do so. Your email is not public on the blockchain, don't share your BOINC email (malicious users could attack your BOINC presence).
If you accidentally clicked 'Cancel' or you're switching from investor mode, you can simple enter your email address into the "gridcoinresearch.conf" config file manually. Use the following format within the conf file:
If you installed the BOINC client anywhere other than the default installation location, you'll need to specify where you installed BOINC in the gridcoinresearch.conf file.