Simply. On the https://soilgrids.org/ portal just click on the download bottom.

You are asked to "Click on the map to select a 2 x 2 degree tile (about 200 by 200 km)", then you can select a layer (a primary soil feature). Download and you get it.

download the complete global map(s) in VRT format. https://www.isric.org/explore/soilgrids

Check https://www.isric.org/explore/soil-geographic-databases

You can also try this

http://www.fao.org/soils-portal/data-hub/soil-classification/world-reference-base/en/

@Kiprotich Kiptum thank you for your kind response

Kiprotich Kiptum Chinaza Godswill Awuchi Shubham Anil Durgude Thank you for sharing valuable iformation.

I want to know how you solved this problem eventually, cause I'm trying to download the global soilgrids250m data now

from where we get soil classes attributes information while we download soil raster data in Tiff format