How to make interwoven/overlapping paths?

[Summayah5FC7]

I want to make paths overlap alternately.

I used outline stroke and shape builder.

But now shape builder is not recognising one of the paths (i.e. when i hover over it it doesn't highlight it?

[Monika Gause]

Paths need to be selected. Are they?

[Summayah5FC7]

Yes it was selected.

Is it because on that particular path i clicked unite (in pathfinder)?

[Monika Gause]

Can you please show a sreenshot of what you have selected and tell us what you want to do with the shapebuilder?