Monoslope Roof

Hi guys. I am a new user in staad. I tried modeling my file but i can't run it as a whole. Can someone give me tips on how to model this on my staad? 

at the same time, i am trying to analyze it part by part, but can't seem quite to run it due to instability errors. Please help me on how to run this structure as a whole. This is my trial partial staad file. 

Thank you in advance for those who will help me. God Bless.

STAAD SPACE DXF IMPORT OF ROOFING STADIUM.DXF
START JOB INFORMATION
ENGINEER DATE 08-Sep-18
END JOB INFORMATION
INPUT WIDTH 79
UNIT MMS KN
JOINT COORDINATES
1 -81798.6 5080 -10217.5; 2 -90637.8 4699 -6153.49; 3 -81798.6 4699 -6153.49;
4 -90638 5194.3 -11437; 5 -90637.8 4965.7 -8998.29;
6 -90637.8 4851.41 -7779.15; 7 -90637.8 4737.1 -6559.89;
8 -90637.8 4508.5 -4121.49; 9 -90637.8 4622.8 -5340.69;
10 -81798.6 5194.31 -11436.7; 11 -81798.6 4965.7 -8998.29;
12 -81798.6 4851.41 -7779.15; 13 -81798.6 4737.1 -6559.89;
14 -81798.6 4622.8 -5340.69; 15 -81798.6 4508.5 -4121.49;
16 -86218 5194.31 -11436.7; 17 -84008.4 4508.5 -4121.49;
18 -88428 4508.5 -4121; 19 -90637.8 5080 -10217; 20 -86218.2 4508.5 -4121.49;
21 -88427.8 5194.3 -11436.9; 22 -84008.2 5194.31 -11436.8;
24 -86218.2 4851.4 -7779.1;
MEMBER INCIDENCES
2 16 20; 3 19 1; 4 5 11; 5 6 12; 6 7 13; 7 9 14; 8 8 15; 10 21 18; 11 4 8;
13 22 17; 14 10 15; 15 4 10;
START GROUP DEFINITION
MEMBER
FLOOR
_ROOF 2 TO 8 10 11 13 TO 15
GEOMETRY
END GROUP DEFINITION
DEFINE MATERIAL START
ISOTROPIC STEEL
E 205
POISSON 0.3
DENSITY 7.68195e-008
ALPHA 1.2e-005
DAMP 0.03
TYPE STEEL
STRENGTH FY 0.2532 FU 0.4078 RY 1.5 RT 1.2
END DEFINE MATERIAL
CONSTANTS
MATERIAL STEEL ALL
MEMBER PROPERTY AMERICAN
2 TO 8 10 11 13 TO 15 TABLE ST W6X8.5
SUPPORTS
1 19 PINNED
2 3 FIXED
MEMBER OFFSET
3 TO 8 15 START -1219.2 0 0
3 TO 8 15 END 1219.2 0 0
2 10 11 13 14 START 0 114.3 -1219.2
2 10 11 13 14 END 0 -114.3 1219.49
MEMBER RELEASE
3 TO 8 15 START MPX 0.99
3 TO 8 15 END MPX 0.99
2 10 11 13 14 START MPZ 0.99
2 10 11 13 14 END MPZ 0.99
SLAVE ZX MASTER 24 JOINT 4 TO 18 20 TO 22
DEFINE WIND LOAD
TYPE 1 WIND 1
SNIP 1985 PRESSURE 1.27454e-006 TERRAIN A CLASSIFICATION 3
EXP 1 JOINT 1 TO 22
DEFINE REFERENCE LOADS
LOAD R1 LOADTYPE Dead TITLE REF LOAD CASE - DL
SELFWEIGHT Y 1 
ONEWAY LOAD
_ROOF ONE 0.3 GY INCLINED
LOAD R2 LOADTYPE Wind TITLE REF LOAD CASE - WL
ONEWAY LOAD
_ROOF ONE 1.275 GY INCLINED
END DEFINE REFERENCE LOADS
LOAD 3 LOADTYPE Dead TITLE DEAD
SELFWEIGHT Y -1 
REFERENCE LOAD
R1 1.0 
LOAD 5 LOADTYPE Wind TITLE WIND
SELFWEIGHT Y -1 
REFERENCE LOAD
R2 1.0 
LOAD COMB 1 GENERATED NSCP-2015 AISC/LRFD 1
3 1.4 
LOAD COMB 2 GENERATED NSCP-2015 AISC/LRFD 2
3 1.2 
LOAD COMB 4 GENERATED NSCP-2015 AISC/LRFD 4
3 0.68 
PERFORM ANALYSIS
PARAMETER 1
CODE AISC UNIFIED 2005
PERFORM ANALYSIS
PRINT CG
FINISH