Thailand (Time to process: 20 minutes)
As you enter the compound, keep to the right lane. The left lanes are for coaches and foot passengers.
Park at the side of the road before you get to the booths. Go to the first booth (the one closest to you when you park) where you sort the immigration aspects.
Then walk to the last booth, which deals with your Carnet and customs formalities, incluidng the paperwork issued by the Thai customs on entry. Here, they complete all the paperwork, and then take a photocopy of the completed Thai-paperwork, which they give to you for your records.
Then drive over the Mekong bridge to the Laos border.
Laos (Time to process: 30 minutes)
The Lonely Planet Guide (4th edition) advises that you need to complete various paperwork for the Laos Customs Authorities, which requires a knowledge of the Thai or Laos languages, and that these forms can be completed in Nong Khai for 7000 to 8000 Baht.
This is nonsense. Just drive up to the border, and cross it like any other.
Before you enter the border compound, there is a road cross-over point: Laos drives on the right, whereas Thailand drives on the left.
Park under the shelter. For your visa, go to the "Visa on Entry" counter on the left - the first counter you come to, on the end of the block. This will cost $31, which gives you 15 days in the country. The sections on the form which requires you to advise the place you'll stay, and a person you know in Laos do not need to be completed. You need passport-sized photos.
Take your passport (with visa) to the centre booth of the three on the pavement under the shelter. They will complete all the immigration formalities.
Then take your Carnet up to Office No 8 on the first floor of the customs block. The door with the stairs to take you upstairs is to the right of the Customs counter, which is just to the left of the Immigration kiosk. Note that this office only has English translation facilities until 4pm. In this office, the entry-coupon is removed from your Carnet by the customs boss, and signed.
Take your carnet downstairs to the Customs counter, and the Carnet counterfoil is stamped.
Back to your car and drive into Laos. There was no check on the exit of the customs compound. Would it be possible to just drive through?!
Note that there is building work ongoing in the Laos Immigration/Customs area. This information may therefore change.