Step 1: create a part of a slider: https://osu.ppy.sh/ss/9487386
Step 2: create another part that will be part of the slider: https://osu.ppy.sh/ss/9487372
Step 3: put te start of the second part of the slider in the end of the first part (in the time line): https://osu.ppy.sh/ss/9487376
Step 4: select both parts: https://osu.ppy.sh/ss/9487389
Step 5: clic on an option that allows you to combine all the parts.
And the final slider should looks like this: https://osu.ppy.sh/ss/9487440 (it isn't perfect because I made it manually).
Step 2: create another part that will be part of the slider: https://osu.ppy.sh/ss/9487372
Step 3: put te start of the second part of the slider in the end of the first part (in the time line): https://osu.ppy.sh/ss/9487376
Step 4: select both parts: https://osu.ppy.sh/ss/9487389
Step 5: clic on an option that allows you to combine all the parts.
And the final slider should looks like this: https://osu.ppy.sh/ss/9487440 (it isn't perfect because I made it manually).