Simplify the following text for a Grade 8 native English-speaking person.
Original: When the filibusters of the Nicaraguan movement realized what was happening in Costa Rica , they sent troops , under the leadership of colonel Schlessinger , which entered Costa Rica through the road that joined Nicaragua with Liberia and which passed by the Hacienda Santa Rosa , where they arrived on 19 March .
Simplified: When the filibusters found out what was happening in Costa Rica , they sent troops . Their troops got to Hacienda Santa Rosa on March 19th .