Singapore and Malaysia just shared the continent so it’s possible you can take a flight a bus and a train between this countries . In my case, I take a bus from Singapore which I landed from changi Airport, terminal 2 go down in lower level and follow the sign bus. Then get the travel map where you can get it in airport for reference on where you go
In your case , I have to go to to Kuala Lumpur so you have to walk 10 minutes following the outside pedestrian bridge where you can see the yellow building called golden mile complex go down and walk to get there . Then after crossing the highway go inside the stalls where agents are selling tickets going to any places in Malaysia In my case I have to
connect via Kuala Lumpur because the trip to Ipoh is in the night time so I take the day trip and the lady who sells the ticket told me I can get cutting trip to Ipoh which I had to pay 15 Singaporean dollar and I also bought a sim card for 15 M5 SIM card Singaporean to connect a host to ipoh .
The name of the agent I booked is pacific express which they had also money changer the bus is air condition with sri lanka driver the trip to Kuala Lumpur or the bus will drop you to tbs terminal .the rides takes 6 hours approximately and the bus departs at 9.30 am with two stops for immigration stamps one in your way from Singapore and the next will be the arrival in Malaysia it shouldn’t take too long around 5 minutes in every stamp