Tick the permission bits, or type 755. The octal and the symbolic form stay in step, and nothing is sent to a server.
A Unix permission mode is three groups of three bits: read, write and execute, for the owner, the group and everyone else. Read is worth 4, write is worth 2 and execute is worth 1. One octal digit holds one group, which is why chmod takes a number such as 644.
A fourth octal digit, on the left, holds setuid (4), setgid (2) and the sticky bit (1). The symbolic form is what ls prints: rwx, a dash where a bit is off, s or S for setuid and setgid, and t or T for the sticky bit.
644
rw-r--r--
755 4755
rwxr-xr-x rwsr-xr-x
777 read as decimal seven hundred seventy-seven
777 read as octal, rwxrwxrwx
A lowercase s means the special bit and execute are both on. An uppercase S means the special bit is on and execute is off. The same pair is t and T for the sticky bit. That is the notation of ls.
An unreadable octal or symbolic value keeps the previous mode. A symbolic string may start with a file-type character such as d or -, as in the first column of ls.
A file created with mode 666 and umask 022 ends up as 644. A directory created with mode 777 and the same umask ends up as 755. The umask clears bits; it does not add them.
The share link stores the octal digits, including a leading special digit when one of those bits is on. The switches and the symbolic form are computed again when the link is opened.
Octal is a natural fit because each permission group is three bits, and one octal digit is three bits. 7 is 111 in binary, which is read, write and execute together.
The sticky bit on a directory, as on /tmp with mode 1777, lets a user delete a file only when they own that file. On a regular file the sticky bit is a historical “keep me in swap” flag that modern systems ignore.