Welcome 

Here I will show you how I build a song from scratch. This song is called "Forgotten Memories"

First off I get my chord progressions. With this song we will keep it simple. Instead of playing a rhythm with the Guitar I will play the chords on the Keyboard. A chorus will be 30 bars 4/4 time with a tempo of 95 beats per Minute. It's in the key of C and has only 4 chords, we will use a I, IV, I, V chord progression with a Dm as a transition. So we start off with a C Chord then F chord back to C then transition Dm, G, Back to C twice, then for the Bridge we will use F, G, F, G, C then do it all again for for 4 Choruses. Basically we will be building this song with one finger notes. So I open up my recording software and record the chords, here I'm just playing my midi keyboard with one finger laying down the foundation of the song. I just counted 1,2,3,4 to the metronome, 4 bars of C, 2 bars of F, 2 bars of C, again 1 bar Dm, 1 bar G, 2 bars C, for 12 bars then 12 more and then 6 bars 1 bar F, 1 bar G, then 1 bar F, 1 bar G, then 2 bars C. That's the whole song. For this Example I only recorded 1 chorus the whole song has 4. 

Now that we have the foundation I like to add the drums so we get a sense of how the beat is going to go. I thought a Latin style might be nice so I opened my Drum program and found a nice beat that I thought might work.

Next comes the Bass line so we add a simple bass line using the same notes as the foundation. C, F, C, D G.

As you can see we have the beginning of a song, now I like to add some more background sounds so I added some strings still basically a one finger addition. Here I just played each note of the chord or just played the chord. We have the start of a pretty nice backing track now, we could play against it with the Guitar or Piano I chose the Piano as it's easier to do a melody.

Now it's time to come up with some sort of Melody. So I just played a simple one note one finger melody.

Wow it's starting to sound like a song, Now it time to start adding some Rhythm to the mix. So I got out my Guitar to lay down a Rhythm track. Needs a lot of work but you get the idea. These are raw tracks no EQ yet so the bass is pretty loud right now and the Rhythm Guitar is way to twangy but it stands out so you can hear it.

Here is the whole song so far all 4 choruses still needs a lot of work but it's came a long way from the Foundation chords.