1) Tune in to a station :
Press "RADIO" + "GOTO" + "<" or ">" to find the station
alternatively, if you know the frequency of the station (eg 102,3)
Hit "RADIO" + "GOTO" +"1" + "0" + "2" + "3"
2) Store to a preset :
"PRESET" and the first vacant preset number will blink, then "STORE"
But you can overrule this "suggested" preset number by pressing
"PRESET" + "X" or "X" + "X" to store the station to preset number of your choice and "STORE"
PS: 
Get a Silver or Gold membership and download the user manual ...