2.) when you open picsart you need to click on pen icon. then you click on collage and you will have three options; grid, frame and background. in this case you will need grid. so after that you will click on portrait (3:4) and choose this thingy with three stripes.
3.) then you need to choose your pictures but make sure that middle one is white and that your border is on zero.
4.) then you will click this thing in corner and make white border the smallest. after that you just click on check mark.
5.) now just screenshot this;
6.) so now you will click on add photo and add ripped paper effect. then you will click on normal and then on lighten.
7.) now just click on check mark, save the picture in your library, add text and you should have something like this;