The linked articles have most of what you need. You need to be able to download the release package, unzip it and upload files with an ftp client lke FileZilla as indicated in the upgrade link I provided.
If a user.config file is already present the connection string is probably there, if not its in Web.config and you should do as it says in the linked user.config article. Copy the user.sample.config file, save uas user.config and then harvest the connection string from Web.config and put iot in user.config this makes it easier t upgrade without losing your custom settings like connection string.
The name of the connection string depends on the db platofrm ms sql or my sql, for your host, just look, you will see it, ther is a connection string in there for each platform but you only care about the one for the db you are using.
You should download mojoprtal-2-2-8-2-c-mssqlreleasefiles.zip
If you are using MySql then you have to also download the mysqldataleyer zip, extract it and copy ther dlls into the wwroot/bin folder of the ms sql version, then upload the copntents of wwwroot to the root of your web using ftp. Don't upload all at once, do as indicated int eh linked upgrade document, copy /Setup folder up first, then Data, then ClientScript, then the rest.
After all files are uploaded visit yoursiteroot/Setup/Default.aspx and it will run upgrade scripts on the database
Watch carefully make sure there are not transfer errors when uploading if there are then keep trying until all the files succeed.
Hope it helps,