Creating a time variable in SPSS

I have just started with my research project. My supervisor asked me to do some simple stuff with the dataset in SPSS. Unfortunately, I don't have a clue of what I'm doing in SPSS. Could anyone help me?

I'm supposed to do a mixed linear model analysis, but right now I'm just preparing the dataset for this analysis.. What that means is that I have a whole bunch of variables, including "ID", "age" etc. However, I have to create a new variable called "time". I have to create four time stamps for each "ID". Is there an easy way to do this in SPSS? Or do I have to do it manually?

I have created two tables to describe the problem better.

This is how the dataset looks right know:
Skjermbilde 2018-06-13 kl. 16.18.55.png
This is how the dataset should look like:
Skjermbilde 2018-06-13 kl. 16.19.11.png
I am forever grateful if anyone can help me with this.