You can use the csv-import component.
See: https://github.com/pelias/csv-importer
An example I've used in the csv file:
name,source,layer,lon,lat,number,street,unit,city,district,region,postcode,id,addendum_json_custom
123 JACKSON AVE,custom,address,-86.66,40.7666,344,JACKSON AVE,,PERU,,IN,46970,651ds651d651,"{ ""customInfo"":""Something Custom"" }"
123 S 600 E,custom,address,-86.66,40.7666,4503,S 600 E,,PIERCETON,,IN,46562,651ewd2332e,"{ ""customInfo"":""Something Custom"" }"
Be sure to use the double quotes in the addendum json as specified in the documentation.
If you are doing Points of Interest, then you may choose a different layer like venue.
You will have to configure the pelias.conf with the source of the files for inport and the api target to specify the source > layer.
As for installation, I've found the dockerized situation to be best for getting started.
https://github.com/pelias/docker