Once you've stopped, lldb will choose a current thread, usually the one that stopped "for a reason", and a current frame in that thread (on stop this is always the bottom-most frame). Many the commands for inspecting state work on this current thread/frame.
To inspect the current state of your process, you can start with the threads:
(lldb) thread list
Process 46915 state is Stopped
* thread #1: tid = 0x2c03, 0x00007fff85cac76a, where = libSystem.B.dylib`__getdirentries64 + 10, stop reason = signal = SIGSTOP, queue = com.apple.main-thread
  thread #2: tid = 0x2e03, 0x00007fff85cbb08a, where = libSystem.B.dylib`kevent + 10, queue = com.apple.libdispatch-manager
  thread #3: tid = 0x2f03, 0x00007fff85cbbeaa, where = libSystem.B.dylib`__workq_kernreturn + 10
The * indicates that Thread 1 is the current thread. To get a backtrace for that thread, do:
(lldb) thread backtrace
thread #1: tid = 0x2c03, stop reason = breakpoint 1.1, queue = com.apple.main-thread
 frame #0: 0x0000000100010d5b, where = Sketch`-[SKTGraphicView alignLeftEdges:] + 33 at /Projects/Sketch/SKTGraphicView.m:1405
 frame #1: 0x00007fff8602d152, where = AppKit`-[NSApplication sendAction:to:from:] + 95
 frame #2: 0x00007fff860516be, where = AppKit`-[NSMenuItem _corePerformAction] + 365
 frame #3: 0x00007fff86051428, where = AppKit`-[NSCarbonMenuImpl performActionWithHighlightingForItemAtIndex:] + 121
 frame #4: 0x00007fff860370c1, where = AppKit`-[NSMenu performKeyEquivalent:] + 272
 frame #5: 0x00007fff86035e69, where = AppKit`-[NSApplication _handleKeyEquivalent:] + 559
 frame #6: 0x00007fff85f06aa1, where = AppKit`-[NSApplication sendEvent:] + 3630
 frame #7: 0x00007fff85e9d922, where = AppKit`-[NSApplication run] + 474
 frame #8: 0x00007fff85e965f8, where = AppKit`NSApplicationMain + 364
 frame #9: 0x0000000100015ae3, where = Sketch`main + 33 at /Projects/Sketch/SKTMain.m:11
 frame #10: 0x0000000100000f20, where = Sketch`start + 52
You can also provide a list of threads to backtrace, or the keyword "all" to see all threads:
(lldb) thread backtrace all You can select the current thread, which will be used by default in all the commands in the next section, with the "thread select" command:
(lldb) thread select 2 where the thread index is just the one shown in the "thread list" listing.