I don't understand byte_jump with from_beginning

Hi I look at rules NETBIOS SMB-DS umpnpmgr PNP_QueryResConfList unicode
little endian attempt (sid=3999)
alert tcp $EXTERNAL_NET any -> $HOME_NET 445 (msg:"NETBIOS SMB-DS
umpnpmgr PNP_QueryResConfList unicode little endian attempt";
flow:established,to_server; flowbits:isset,dce.bind.umpnpmgr;
content:"|00|"; depth:1; content:"|FF|SMB%"; within:5; distance:3;
byte_test:1,&,128,6,relative; pcre:"/^.{27}/sR"; content:"&|00|";
within:2; distance:29; content:"|5C 00|P|00|I|00|P|00|E|00 5C 00 00
00|"; distance:4; nocase;
byte_jump:2,-17,relative,from_beginning,little; pcre:"/^.{4}/sR";
content:"|05|"; byte_test:1,&,16,3,relative; content:"|00|"; within:1;
distance:1; content:"6|00|"; within:2; distance:19;
reference:url,http://www.microsoft.com/technet/sec...ms05-039.mspx;
classtype:protocol-command-decode; sid:3999; rev:1;)

why after rule option
“byte_jump:2,-17,relative,from_beginning,little; pcre:"/^.{4}/sR"”,
the doe_ptr at 0x58。
I don’t understand “byte_jump:2,-17,relative,from_beginning,little;
pcre:"/^.{4}/sR"” how to work？