Usually (before the digital time) a zoomlens was not capable to do Macro.
Macro is 1:1 or closer. We all use for figures closeup fotografie, and some real Macro.
If i see that your lens has his smallest diafragma to 4, you need alot of light to get some sharping into the depth.
Use the setting Diafragma priority and set that as D 8 maybe 11 and let the camera choose the shutterspeed.
I think you have to use a tripod, and the timer.
Take alot of pictures and set the D higher to 16 and 22.
I think the slide button on the lens is to set the lens fixed at the choosen mm.
Marc