If you know the notes of chords, you can walk. First you should learn two beat (two half notes per bar, I and V), and then four beat (quarters, play I I V III).
Say you see a C7, you play C E G Bb (I III V VII upwards) or C Bb G E (I VII V III downwards). The next chord gives you the first note, and the position in the fretboard suggests the direction, up or down. Then you can modify the walk by octaves, triplets and other melodic, and rhythmic ideas. Do not forget two, and four beat here.
Start with a slow version of Autumn leaves. Listen to it a couple of times. Find the chords and start playing. Make it slow, starting from two beat, and you'll amaze yourself.